The instant invention is generally directed to a controlled environment processing chamber or chambers in which parts are to be dried. More specifically, the present invention is directed to a controlled processing method for the drying of parts during the final finishing step.
Typically, the final step in the finishing of metals, plastics, ceramics, composites and other materials often is a drying process. This step in the process is a step that is often overlooked from the cost and efficiency perspective. However, the cost associated with poorly dried parts can be seen in that it leads to future problems such as corrosion, poor adhesion, and peeling and at minimum an unattractive cosmetically prepared piece. In addition, the drying step may become a significant cost factor especially if energy prices are high.
Therefore it is a desire of the present invention to provide a faster, more efficient, lower cost parts drying method. For the purposes of the present invention the method described herein will be discussed in comparison to traditional forced convection air-drying in order to emphasize the difference in the method of the present invention from traditional techniques, as well as to compare the important improvements and cost savings associated with the present method.
In this regard, as stated above, the present invention is directed to a controlled environment processing chamber or chambers in which parts are to be dried. The parts either contain water on or imbibed into the part. The process includes a means of applying a negative gauge pressure to the chamber to remove air or other non-condensable gases. Means are provided for introducing a solvent in a vapor state. A first system recovers water or aqueous solution(s) from the object being dried and the chamber. A second system, separate from the first system, further recovers residual solvent from the object and chamber after the drying process.
In another aspect of the invention, a method of processing an object in an enclosed solvent processing system is provided. The process includes a solvent or steam supply system in sealable communication with an enclosed chamber and includes the steps of:
a) sealing the solvent or solution supply system with respect to the chamber;
b) evacuating the supply system of air and non condensable gases and maintaining this air free environment;
c) opening the drying chamber to atmosphere and placing an object to be dried in the chamber;
d) evacuating the drying chamber to remove air and other non-condensable gases;
e) opening the drying chamber with respect to the solvent supply system and introducing a solvent or solution into the evacuated chamber;
f) opening the drying chamber with respect to a closed circuit vapor recovery system;
g) continuously introducing and removing vapor from the chamber to continuously remove water from the part and chamber;
h) continuously removing water and drying the object while maintaining an air free environment within the chamber;
i) recovering and processing the solvent and water removed from the chamber within the closed circuit processing system;
j) sealing the chamber with respect to the atmosphere;
k) opening the chamber with respect to a closed circuit vapor recovery system recovering and recycling the solvent introduced into the chamber within the closed circuit processing system;
l) sealing the chamber with respect to the solvent supply system closed circuit solvent processing system;
m) introducing air or other non condensable gases into the chamber for sweeping further solvent on the object and within the chamber; and
n) opening the chamber and removing the treated object.
The main objective of this invention is to remove water or an aqueous solution from an object in a manner that is faster and better from an economic and efficiency standpoint than air or vacuum drying. In order to accomplish this, a solvent, which is insoluble or sparingly soluble in water, is used to remove water as vapor from a part and drying chamber. Another main objective of this invention is to dry water or an aqueous solution from a part rapidly so as to save energy. Another main objective of this invention is to dry water rapidly so as to disrupt the surface or pores of a part thereby removing foreign material from the part. Another main objective of this invention is to dry water rapidly so as to prevent water spotting on the part. Another main objective of this invention is to combine the water drying of a part into a one step process with cleaning of the part with a solvent.
Another object of this invention is to provide an improved closed circuit solvent system and method, which enables solvent recovery and limits hazardous emissions. The invention can employ a variety of solvents having boiling points as low as 70 degrees Fahrenheit and as high as 500 degrees Fahrenheit. Another object of this invention is to provide a means of recovering solvents using water or other hydrophilic solvent to provide the same benefits as outlined for water drying above.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.